The present invention is directed to a drilling and chiseling tool bit for working on concrete, rock, masonry and the like, and the tool bit includes a tool bit head, a shank extending from the head to an insertion end and the insertion end is arranged to be engaged with rotational driving means.
Drilling and chiseling tool bits for work on rock are acted on by a driving device, such as a drill or a chisel hammer which imparts relatively high percussion energy to the tool bit. The percussion energy is transmitted from the rear insertion end through the shank to the tool bit head. Percussion energy is divided in the tool into kinetic energy of the center of gravity movement and into vibration energy.
The kinetic energy acts practically exclusively for working on the receiving material. Vibration energy, however, produces vibrations in the tool bit which generates sound radiation and stresses in the bit. The vibration energy contributes little if any work on the receiving material.
Especially long tool bits have low natural frequencies. This can be explained by the circumstance that one vibration period, that is, the time required for sound waves to travel from one sound transmission surface to another sound transmission surface and back, is relatively long. If this time period is longer than the percussion or blow transmitting time period, during which the tool bit contacts the ram or piston of a percussion device, then the natural vibration of the tool bit is excited and a practically unopposed sound vibration is generated which is very unpleasant for the operator and can lead to the damage or destruction of the tool.